More than a century of oil and gas drilling has left millions of wells abandoned around the world, many of which still emit powerful greenhouse gases such as methane.
There are more than two million such wells in the United States alone. And the non-profit Well Done Foundation is trying to seal some of these wells.
To seal and trap the methane gas underground, the well must be closed by pumping the concrete mixture into the well.
Methane levels need to be monitored for months, and someone needs to pay for the project. In this case, it's a local oil and gas company called Seneca Resources.
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